The present invention relates to a reflective optical element based upon a reflective film, tape, or sheet applied to an optically shaped surface. In particular, the present invention relates to a spectacle and goggle mounted display and viewer that uses an inside concave portion of a lens surface for a reflective optical element and mirror.
Many spectacle and goggle mounted devices require at least one reflective element or mirror. Examples of such applications are glasses mounted displays and glasses mounted mirrored viewers for cyclists.
To apply a silvered or aluminized reflective surface to a small portion of an eyeglass lens for a display or viewer requires the attention of a specialized laboratory. About half of the population wears prescription glasses and would be adverse to giving them up for disassembly and further lab work to obtain a display. Sunglasses used by those with normal vision are selected for style and purchased for use without delay for laboratory work. Thus the delay and inconvenience of sending eyeglasses to a mirroring laboratory is a hindrance to making glasses mounted display devices readily available and widely acceptable.
For spectacle mounted displays with large numerals such as a digital clock, the precision and cost of masking and sputtering a protected aluminized coating onto a glasses lens surface has proven to be a costly and overly precise optical response. While an aluminized coating may provide an excellent optical image of the object, in this case four numerals, such precision of image is unnecessary for the user to be able to discern the time correctly.
In order to overcome the shortcomings of the current condition, the present invention is directed to a reflective optical element comprising a lens possessing at least one optically shaped surface a portion of which is suitable as an adhesive substrate on which is disposed a lens film comprising an adhesive layer and backing selected to maintain a uniform thickness when deformed, a metal foil and metallized polymer layer possessing a uniform light reflecting surface and of a thickness selected to be flexible when deformed, wherein said lens film is applied and secured to said lens with pressure and stress to conform to said optically shaped surface and adhere said adhesive backing to said lens substrate. Said light reflecting surface is selected and positioned within the optical train of a spectacle mounted display and viewer. In some embodiments of the present invention, the lens film is partly transparent. In the preferred embodiment of the current invention as a spectacle mounted display, the resulting image quality is suitable for the display of a limited quantity of text.
In the prior art, reflective tape was considered to be too imprecise a medium for functioning as an optical element to generate a recognizable image. Although metallized film is readily available as flat mirrors for decorative purposes, spherical, cylindrical or aspheric shapes in small sizes lens were considered unlikely to produce acceptable images for any possible application.
It is the object of this invention to provide an immediate and easy application of a reflective layer to an optical surface of a glasses or goggles mounted display.
It is also an object of this invention to provide a reflective surface of a quality that is consistent with the legibility and accuracy of simple, limited text and graphic images by a glasses or goggles mounted display such as used in a pager, cellular phone, or personal digital assistant. Personal glasses mounted displays must minimize the area they occult to maintain forward viewing. For purposes of this invention the definition of simple, limited text is taken to be fewer than 25 vertical lines of text. Such text when displayed at letter heights of 0.3 degree or greater minimizes the effects of reflective surface imperfections.
It is a further object of this invention to provide a reflective coating that can be applied under field rather than laboratory conditions.
It will be understood by one skilled in the art that protective means may be applied to the reflective metal layer to protect against scratches. Such a protective means may consist of two protecting transparent layers wherein at least one protecting layer is disposed on each face of said reflective metal layer.
It will also be understood by one skilled in the art that by the use of a transparent adhesive that the current invention can be applied to the front surface of a spectacle lens. In this case a light ray from the object will pass through the spectacle lens and the adhesive layer to be reflected back through the adhesive and the spectacle lens.
It will further be understood by one skilled in the art that a metallized film may be selected to be partly transparent to provide a forward view through the glasses as well as a reflective view of the image. In such an application a transparent adhesive such as 3M Optically Clear Laminating Adhesives 8141 and 8142 would be selected so as not to hinder forward viewing.